voltage across battery when charging ?

[Mustang_289]

checked the + and - cables last night, no short between them. I even checked the disconnect switch it's working like it's supposed to.

We brought in an alt off a friend of my son's car. Put that alt on, still reading 12.3 volts. I told my son I'm a little concerned about the vortec supercharger bracket grounding properly to the engine block, as the block came painted from Keith Craft. So we ran another ground from one of the alt bolts to the frame. We took another reading and read about 13.3, this was very positive. Here's where it gets freaky. We took off that alt, put back the PA Performance alt on, and took another reading at idle and we're back to 12.3 volts.

I was also thinking that if we had something in the car loading the system, wouldn't a fuse pop, as all electrical runs through the fuse panel right? Only difference is some circuits are switched by ignition, and some circuits are live all the time.